Gun mount



J NOV- 5, 1946. J c, TROTTER 2,410,614-

GUN MOUNT Filed June 28, 1944 IN V EN TOR. JOHN C. TROTTER Patented Nov.5, 1946 when .--=umrsn stares Parent OFFECE GUN MOUNT John C.TrottenBurlington, Vt,, assignor to Bell 1 Aircraft CorporationApplication June 28, 1944; Serial No. 542,499

3 Claims.

Thi -invention relates to gun mounts, and more particularly to fixed-aimtype mountings for aerial machine guns and cannon or the like. Such gunmount devices customarily embody a pair of gun connection unitsextending from the airplane fuselageor wing or other frame structureuponwhich the gun is to be mounted; said connection units being relativelyspaced in the direction of the longitudinal extent of the gun andgenerally referred to as -the front trunnion and rear-trurmion,respectively. The front trunnionunit is customarily provided in the formof a swivel connection device whereby the gunmay be rocked thereon abouttransverse axes for regulatingv the aim of the gun relative to thesupporting frame. The rear trunnion unit customarily comprises alaterally and vertically adjustable linkage between the mounting-frameand the gun, whereby to providefor pivoting of the gun upon the front..mount device for aim adjustment purposes.

1 For example, manufacturing tolerances which are necessary inconnection with large airplane productionprograms and varying tacticalrequirements calling for different rates of plural gun fire convergencesrequire that for such purposes must embody. aim adjustment means for theguns relative to the airplane fuselage or wing structures, as explainedhereinabove. Prior art' arrangements' for. providing the adjustabilityfeatures referred to hereinabove usually employ paired screw threadconnection devices having transverse axes forconnecting the gun andsupport frame elements, whereby screw adjustments thereof obtaincorresponding lateral and vertical adjustments of the rear end portionof the gun relative. to the supporting frame, whereby the gun aim isshifted about the front trunnion, while keeping the gun locked inmountedposition. 'Such adjustments of the screw threadconnection devices are,howeifenaccoinbli'shed through use of wrenches or other tools thereon asin l atent No. 2,076,256, for example, and it is usually extremelydifficult to design the gun mount and airplane frame structures so as toinake adequate provision for room sufficient-to allow quick andeffective handling of wrenches or the like in the regions of the screwdevices referred to. Also, under such conditions it is extremelydiificult to effect relatively minute andaocurateadjustments of thescrew devices.

Itis a primary object of the present invention to provide an improvedaim-adjustable gun mount device. .as an improvement over the StandardArmyv Type A GunRear' 'Irunnion, forexample, andwhich-is of rugged andcompact formand adapted to be accurately adjusted with improved facilitywithout the use of wrenches or other tools orthelike. Another object ofthe invention is to: provide a device of the character aforesaid whichis adapted to bemanuallymanipulated by gunserVice personnel withimproved ease and facility to provide micrometer-fine adjustments of themounted gun aim. Another object of the invention is to provide a gunmount. device having the features hereinabove recited and which isself-locking atv all positions of adjustment thereof and requires noaccessory locking means.

ther objects and advantages .of the invention will appfiar I in the(specification hereinafter.

In the drawing": I I

Fig. 1 is an elevation of a gun mount'device of the invention, withportionsshown'in section; and

Fig. 215 a section taken along line II-II of Fig. 1.

Fig. ,3 is airagmenta'ry sectional view. of the device taken along lineIIL-III of Fig. 2.

A gun mountdevice of. the invention i'SillllS". trated 'infthe.drawing-in connection with the mounting-eta machine gun or cannon asindicated at H] upon a frameelem'ent indicated 12. It will .beunderstood that the frame member I2 may beanyportion. of a framingstructure, such as interiorly of the fuselage or wing of'an airplane,and it will also beunderstood that the gun lil--will be preferablyarranged to be carriedat positions spaced longitudinally of the gun-bymeans of a pair of mount connectiondevices, whereby to rigidlymount thegun It upon the frame l2. At the relatively forward position theconnection device may comprise any suitable form of swivelable mount;that is, a connection device permittingthe. gun tobe rotated thereonabout substantially transverse horizontal and vertical axes foradjusting the gun aim in azimuth and elevation relative to the frame l2.Although the present invention may be applied eitherto the front or therear gun mount connection, it is shown in the. drawing herein to relateonly to the rear gun mount connection; and in the interests ofsimplification of the specification only the rear gun mount connectionform of the inventionis described in detail hereinafter.

Thus, as illustrated, the gun mount of theinvention may comprise amounting sleeve It which is externally threaded to extend substantiallyvertically and in screw thread mounted relation upon an internallythreaded ferrule 16 carried by the frame structure I2. The upper end ofthe sleeve I4 is rotatably heldagainst a collar 18 by. means of a bolt20 passing throughthe sleeve I4 and provided with a head portion 22which rests against the collar I8 so as to pull downwardly thereon inreaction to the clamping forces of a nut 24 which is screwed upon a stubend portion 25 of the bolt 20 at the lower end thereof. For convenienceof manufacture the threaded stub end portion 26 may be separatelyfabricated and inserted within a suitably bored portion of the bolt 20and keyed thereto by means of a pin 28; and subsequent to final assemblyof the sleeve and collar and bolt elements the nut 24 may be locked uponthe stub 26 by means of a cotter pin 29.

A socket member 30 is arranged to embrace the upper end of the bolt head22, to be rotatable thereon, and the socket member 30 is formed with anintegral extending eye portion 3|; the bore of the eye portion 3I beinghorizontally directed transversely of the longitudinal axis of the gunto be mounted. The eye portion 3| is internally threaded to receive atrunnion unit ineluding a bolt 34 which slip-fits through paired lugs3535 extending downwardly from the gun I!) and formed integral therewithto mount the latter upon the upper end of the gun mount sleeve I4. A key36 is fitted upon the bolt 34 between the positions of the lugs 35-35 ofthe gun to key a sleeve 38 of externally threaded form to the bolt 34subsequent to screwthreaded insertion of the sleeve 38 within the eyeportion 3|. Thus, it will be understood that the displacements invertical directions of the post sleeve [4 relative to the mountingframe. I2 will either raise or lower the elevation of the trunnion bolt34, and thus effect elevational adjustments of the gun aim relative tothe frame I2.

The socket member 30 is arranged to be detachably connected to the bolthead 22 for quick gun dismounting and remounting purposes and to be heldagainst axial movement therewith, when in gun mounting condition by anysuitable means. This may be accomplished through use of a retaining ring40 which encircles the socket member and controls an interconnectiondevice thereon. This feature of the mechanism is not a part of thepresent invention, however, as such quick-disconnect devices arepresently well known in the gun mount art, and may employ for exampleoperative elements of the type shown and described in detail in PatentNo. 1,939,699. The collar I8 is held against rotation relative to thesocket member 35 by means of a number of detent lugs 32 carried by thecollar and engaging notches 33 formed in the lower edge of the socketmember.

To eifect gun aim adjusting vertical displacements of the sleeve l4relative to the frame l2 it is of course onlynecessary to cause thesleeve to rotate relative to the frame, whereby the screw thread devicesthereof will cause the sleeve to correspondingly rise or lower. Whereasto apply manual rotating forces directly to the sleeve I4 would requirethe use of a wrench or the like and would inevitably result inrelatively coarse adjustments of the sleeve I4, the present inventionemploys a novel power supply mechanism which is adapted to be manuallyactuated to translate manual movements thereof into mi- (lnometer-finerotational movements of the sleeve For example, as shown in the drawing,the power supply mechanism may conveniently comprise a casing 44 keyedto a base ring 46 (as by screws 41 shown in Fig. 2) which encircles ashouldered portion of the upper end of the sleeve I4 and is freelyrotatable thereon and main-e tained. against accidental displacementsubsequent to assembly of the device by means of a spring washer 48. Thering 46 carries an upstanding shaft 50 which mounts in freely rotatablerelation a dual gear 52 having gear elements in coaxial relation witheach other and fastened together 'for unison rotation. The lower one ofthe gear elements is of a slightly larger diameter than the upper gearelement thereof. The lower gear element meshes with a ring gear portion55 of the sleeve l4, and the upper gear element meshes with a ring gearportion 56 of the collar l8. Since the collar I8 is non-rotatablyattached through the socket member 30 to the trunnion bolt 34 wheneverthe connector device 45 is in gun mounting condition, any manualrotation of the casing 44by gun servicing personnel will cause the gearunit 52 to be rotated upon the shaft 55 while being simultaneouslycarried by the ring 48 to rotate with .a planetary motion about thevertical sleeve I 4. Such rotation of the gear unit about the shaft 53causes the toothed portion 55 of the sleeve L4 to be simultaneouslydriven to rotate the sleeve about its vertical axis, but the speed ofrotation of the sleeve I4 will be at greatly reduced rate compared tothe speed of manual rotation of the casing 44 because of the slightdifference in diameters of the upper and lower elements of the gear unit52. Thus, it will be appreciated that the speed of rotation of themounting sleeve I4 relative to the speed of manual rotation of thecasing 44 will be governed by the difference be-v tween the diameters ofthe elements of the gear unit 52, and that this may be regulated toprovide any desired degree of rotational speed reduction. A pair ofspring detents 6060 are preferably mounted to extend in cantileverfashion from the base ring 46 to bear at their free ends against thegear unit 52 to impose thereagainst rotationrestraining influences,whereby to retard the power supply unit against accidental rotation.

Thus, it will be understoodthat because of the speed reduction ratiowhich is provided by the gear unit the casing 44 is adapted to be easilyrotated manually by only one hand of the operator even though nearbyportions of the gun and gun mount and frame support elements provideonly restricted room for insertion of the operators hand into actuatingposition, and that thereby the need for applying wrenches or other toolsor the like to the control device is eliminated. Also, it will beappreciated that due to the rotational speed reduction feature of thecontrol unit extremely fine adjustments of the gun mount sleeve [4relative to the frame I2 can be effected without difficulty by theoperator.

As illustrated generally at 65, Fig. 1, an azimuth adjustment controldevice will Preferably be employed in conjunction with the trunnion bolt34 and the gun lugs 35-35; and the adjustment control device maycomprise aunit which is substantially identical to the control unitenclosed within the casing 44. That is, the control unit 65 maycomprisea manually rotatable casing 66 which is dualeared internallythereof to both the trunnion bolt 34 and a sleeve.

about the axis of the trunnion bolt 34 will cause the gear unitinternally of the control device 65 to react against the fixed gun lugandto cause;

the trunnion bolt 34 to rotate within the gun lugs 35--35 at a greatlyreduced speed relative to the speed of rotation of the casing 66. Suchrotation of the trunnion bolt 34 will drive the threaded sleeve 38 torotate within the eye portion 3| of the gun mount post device, whereby acorresponding screw threading displacement of the gun l0 laterally ofthe mounting sleeve M will occur to provide a micrometer-fine adjustmentof the gun aim in azimuth about the vertical axis of rotation of thefront gun mount device.

It will be appreciated that the gun aim adjustment mechanisms of theinvention are freely reversible in the sense that they are readilyrotated in either direction by the operator to procure correspondingreverse-direction adjustments of the gun aim; but that under allconditions of adjustment the mechanisms are inoperable to permit changesin the gun aim in response to forces from any source except when appliedto the control casings 44-66 of the mechanisms. It will also beunderstood that although only one form of the invention has been shownand described in detail it will be apparent to those skilled in the artthat the invention is not so limited but that various changes may bemade therein without departing from the spirit of the invention or thescope of the appended claims.

I claim:

1. A gun support comprising in combination, bolt means formed to beconnected to a gun for support thereof, a sleeve rotatably mounted uponsaid bolt means and formed with external screw threads for screwthreaded engagement upon a positionally fixed frame, means for retainingsaid bolt means and said sleeve against axial displacements relative toeach other, a ring rotatably mounted upon said sleeve, differentiallysized gear means carried upon said sleeve and said bolt meansrespectively, and a pair of differentially sized pinions rigidlyinterconnected and carried by said ring in positionally fixed relationthereon, said pinions meshing with the bolt means and sleeve gear meansrespectively.

2. A gun support comprising in combination, bolt means formed at one endto be connected to a gun for support thereof, a sleeve rotatably mountedupon said bolt means and formed with external screw threads for screwthreaded engagement upon a positionally fixed frame, means for retainingsaid bolt means and said sleeve against axial displacements relative toeach other, a ring rotatably mounted upon said sleeve in axiallynon-displaceable relation thereon, difi'erentially sized gear meanscarried upon said sleeve and said bolt means respectively, and a pair ofdifferentially sized pinions rigidly interconnected and carried by saidring in positionally fixed relation thereon, said pinions meshing withthe bolt means and sleeve gear means respectively.

3. A gun support comprising in combination, a bolt formed to beconnected to a gun for sup port thereof, a sleeve rotatably mounted uponsaid bolt and formed with external screw threads for screw threadedengagement upon a positionally fixed frame, a collar mounted upon saidbolt and fixed against relative rotation with the gun, means forretaining said bolt and said sleeve against axial displacements relativeto each other, a ring rotatably mounted upon said sleeve, gear meansformed upon said sleeve, relatively larger gear means formed upon saidcollar, and a pair of axially aligned pinions rigidly interconnected andcarried by said ring in positionally fixed relation thereon, saidpinions meshing with the collar and sleeve gear means respectively,whereby said ring may be manually rotated relative to said collar toprocure rotation of said sleeve at reduced speed.

JOHN C. TRO-ITER.

